Laminated structures for use in motors and other electrical apparatus have traditionally been formed by stamping laminations from ferrous metal. In the conventional process of producing laminations, the stamping operation controls the metallurgy, for it is necessary that a relatively high carbon steel be used in order to eliminate the formation of burrs during stamping. If a low carbon steel is utilized, burrs will be formed which can cause electrical shorting between adjacent laminations in the electrical apparatus and thus result in substantial eddy current losses.
In the traditional process, the high carbon steel laminations are heat treated after stamping to reduce the carbon content and develop an oxide coating. The laminations are then coated with a resin or varnish and assembled into the laminated structure which is baked at an elevated temperature in order to bond the laminations together.
Because of these operations, the traditional method of forming a laminated structure is labor intensive. The stamping operation not only results in substantial scrap loss, but the stamped laminations require heat treatment to reduce the carbon content and produce an oxide coating. Further cost is added to the final product through the varnishing and baking of the laminated structure.